Patent application title: DRUG DISCOVERY SCREENING DEVICE

Abstract:

An object of the invention is to implement a drug discovery screening
device having high throughput and high accuracy. The drug discovery
screening device is provided with a Nipkow disc type confocal scanner for
irradiating excitation light on samples placed on a well plate, and
executing image processing based on fluorescent signals from the samples,
and comprises a confocal scanner for irradiating a plurality of
excitation lights and to which a plurality of fluorescent signals are
incident, and a plurality of objectives lenses for irradiating a
plurality of excitation lights emitted from the confocal scanner on the
plurality of samples, to which the plurality of fluorescent signals
generated from the plurality of samples are incident, and bringing the
plurality of fluorescent signals to the confocal scanner.

Claims:

1. A drug discovery screening device for irradiating excitation light on
samples placed on a well plate, and executing image processing based on
fluorescent signals generated from the samples, said drug discovery
screening device comprising:a plurality of objective lenses for
irradiating a plurality of excitation lights on a plurality of samples,
respectively, thereby focusing a plurality of fluorescent signals
generated from the plurality of samples;a pinhole array disc to which the
plurality of fluorescent signals are incident through the plurality of
objective lenses; anda plurality of dichroic mirrors for reflecting the
plurality of fluorescent signals passed through the pinhole array disc.

2. The drug discovery screening device according to claim 1, further
comprising a micro-lens array disc for focusing a plurality of excitation
lights to be incident, and bringing the plurality of excitation lights to
the pinhole array disc through the plurality of dichroic mirrors.

3. The drug discovery screening device according to claim 1, further
comprising a plurality of imaging lenses for focusing the plurality of
fluorescent signals emitted respectively form the plurality of objective
lenses on pinhole faces of the pinhole array disc, respectively.

4. The drug discovery screening device according to claim 1, further
comprising a plurality of imaging cameras to which the plurality of
fluorescent signals emitted respectively from the plurality of dichroic
mirrors are incident.

5. The drug discovery screening device according to claim 1, wherein an
interval between two objective lenses is the integral multiple of an
interval between respective wells of the well plate.

6. The drug discovery screening device according to claim 1, wherein four
objective lenses are disposed on each apex of a square having one side
equal to the length of the integral multiple of an interval between
respective wells of the well plate.

Description:

FIELD OF THE INVENTION

[0001]The invention relates to a drug discovery screening device having
high accuracy by use of a fluorescence microscopic system, and
particularly to a drug discovery screening device having high throughput.

BACKGROUND OF THE INVENTION

[0002]In a drug discovery screening device, light having a specific
wavelength is irradiated on samples placed on wells (holes) arranged in
an array on a well plate so as to excite the samples, and fluorescent
images emitted from the excided samples are enlarged by a microscopic
system, so that the enlarged image are acquired by a camera. In this
case, since the fluorescent images are acquired from all the wells, the
well plate is shifted by an X-Y stage.

[0003]Next, the images acquired by the camera are subjected to image
processing, thereby finding a sample which becomes a candidate of
medicines based on the result of image processing. To enhance the quality
of the images, a confocal scanner is disposed between the microscope and
the camera.

[0004]FIG. 6 is a view showing a configuration of a conventional drug
discovery screening device.

[0005]In FIG. 6, a confocal scanner 9 is connected to a microscope 11.
Illuminating parallel excitation light flux 3 (dotted lines) which is
incident to the confocal scanner 9 is converted into individual fluxes by
a micro-lens array disc 4. The excitation light flux 3 transmits through
a dichroic mirror 5 formed of a flat plate mirror having spectroscopic
characterization, and passes through each pinhole of a pinhole array disc
6 (also called as Nipkow disc), then it is focused on a sample 2 placed
on the well plate 1 though an objective lens 10 of the microscope 11,
thereby exciting fluorescent sample. The micro-lens array disc 4 and the
pinhole array disc 6 are rotated around a rotating central axis 8 in a
state where they are mechanically connected to each other by a connection
member 7.

[0006]A fluorescent signal 12 generated by a fluorescent reagent of the
sample 2 passes again through the objective lens 10, and is focused on
each pinhole of the pinhole array disc 6. The fluorescent signal 12
passed through each pinhole is reflected by the dichroic mirror 5,
thereby forming a confocal optical image on a camera 14 through a relay
lens 13. An image processing unit 15 executes appropriate image
processing and data processing for displaying dynamic state of cells and
so forth upon receipt of the image signal from the camera 14.

[0007]With the configuration of the conventional drug discovery screening
device, since a plane on which each pinhole of the pinhole array disc 6
is arranged, a plane on the sample 2 to be observed, and a
light-detecting surface of the camera 14 are disposed in an optical
conjugate relation with each other, an optical sectional image of the
sample 2, i.e. a confocal image is formed on the camera 14. Accordingly,
since the confocal image of the sample 2 can be formed on the
light-detecting surface of the camera 14, when the well plate 1 on which
the multiple samples 2 to be inspected are arranged in a matrix is
shifted relative to the microscope 11 and the confocal scanner 9, the
confocal images of all samples can be acquired by the camera at high
speed.

[0008]The following patent document has been known as a prior art of such
a confocal telescopic device.

[0009][Patent Document 1] JP 2002-062480A

[0010]Meanwhile, according to the conventional drug discovery screening
device, there is only one system of microscope, wherein one objective
lens is disposed relative to one confocal microscope. Accordingly, it
takes time to acquire fluorescent images of a large quantity of samples
which are arranged in a lattice shape, and if the objective lens is built
in a drug discovery screening device, there was a problem in that there
were limitations to throughput as the device.

SUMMARY OF THE INVENTION

[0011]The invention has been made to solve the problem of the prior art
and it is therefore an object of the invention to implement a drug
discovery screening device having high accuracy.

[0012]To achieve the object of the invention, the drug discovery screening
device for irradiating excitation light on samples placed on a well
plate, and executing image processing based on fluorescent signals from
the samples, said drug discovery screening device is characterized in
comprising a plurality of objective lenses for irradiating a plurality of
excitation lights on a plurality of samples, respectively, thereby
focusing a plurality of fluorescent signals generated from the plurality
of samples, a pinhole array disc to which the plurality of fluorescent
signals are incident through the plurality of objective lenses, and a
plurality of dichroic mirrors for reflecting the plurality of fluorescent
signals passed through the pinhole array disc.

[0013]The drug discovery screening device may further comprise a
micro-lens array disc for focusing a plurality of excitation lights to be
incident, and bringing the plurality of excitation lights to the pinhole
array disc through the plurality of dichroic mirrors.

[0014]The drug discovery screening device may further comprise a plurality
of imaging lenses for focusing the plurality of fluorescent signals
emitted respectively form the plurality of objective lenses on pinhole
faces of the pinhole array disc, respectively.

[0015]The drug discovery screening device may further comprise a plurality
of imaging cameras to which a plurality of fluorescent signals emitted
respectively from the plurality of dichroic mirrors are incident.

[0016]The drug discovery screening device wherein an interval between two
objective lenses is the integral multiple of an interval between
respective wells of the well plate.

[0017]The drug discovery screening device wherein four objective lenses
are disposed on each apex of a square having one side equal to the length
of the integral multiple of an interval between respective wells of the
well plate.

[0018]According to the drug discovery screening device of the invention,
it is possible to provide a drug discovery screening device provided with
a multihead microscope function capable of picking up images of a
plurality of samples in a plurality of wells as confocal images thereof
at a time because the drug discovery screening device of the invention
for irradiating excitation light on samples placed on a well plate, and
executing image processing based on fluorescent signals from the samples
is characterized in comprising a plurality of objective lenses for
irradiating a plurality of excitation lights on a plurality of samples,
respectively, thereby focusing a plurality of fluorescent signals
generated from the plurality of samples, a pinhole array disc to which
the plurality of fluorescent signals are incident through the plurality
of objective lenses, and a plurality of dichroic mirrors for reflecting
the plurality of fluorescent signals passed through the pinhole array
disc.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a view showing a configuration of a first embodiment of a
drug discovery screening device according to the invention;

[0020]FIG. 2 is a plan view of a partial configuration of the drug
discovery screening device showing the disposition of each optical
element within a confocal scanner;

[0021]FIG. 3 is a plan view of a partial configuration of a second
embodiment of a drug discovery screening device according to the
invention;

[0022]FIG. 4 is a view for explaining the operation of a well plate in a
first disposition example thereof;

[0023]FIG. 5 is a view for explaining the operation of a well plate in a
second disposition example thereof; and

[0024]FIG. 6 is a view showing a configuration of the conventional drug
discovery screening device.

PREFERRED EMBODIMENTS OF THE INVENTION

[0025]Preferred embodiments of the invention are now described in detail
with reference to the attached drawings.

[0026]FIG. 1 shows one embodiment of a drug discovery screening device
according to the invention, and it is a view for explaining a
configuration of the drug discovery screening device having a confocal
optical dual-system. The same elements as those in FIG. 6 are denoted by
the same reference numerals and the overlapped explanation thereof is
omitted. FIG. 2 is a plan view of a partial configuration of the drug
discovery screening device showing the disposition of each optical
element inside a confocal scanner.

[0027]Two excitation light fluxes 3a, 3b (dotted lines) are incident to a
micro-lens array disc 4 from beneath the figure, and they are converged
into individual fluxes. The excitation light fluxes 3a, 3b transmit two
dichroic mirrors 5a, 5b each formed of a flat plate mirror having
spectroscopic characterization, and pass through individual pinholes of a
pinhole array disc 6, and they are focused on individual samples 2 placed
on a well plate 1 by two imaging lenses 18a, 18b and two objective lenses
10a, 10b of a microscope 110, thereby exciting fluorescent sample.

[0028]When the samples 2 are excited by two excitation light fluxes 3a, 3b
each having a specific wavelength, they generate fluorescent signals 12a,
12b (solid lines in FIG. 1) wavelengths of which are longer than those of
the excitation light fluxes 3a, 3b. The fluorescent signals 12a, 12b are
focused on the objective lenses 10a, 10b and the imaging lenses 18a, 18b
in the microscope 110, and form images on the surfaces of individual
pinholes of the pinhole array disc 6 within a confocal scanner 90.

[0030]Meanwhile, with the foregoing configuration of the drug discovery
screening device, it is assumed that an interval between two objective
lenses 10a, 10b is equal to the integral multiple of an interval between
respective wells of the well plate 1.

[0031]The dichroic mirrors 5a, 5b are designed to have characteristics
through which the excitation light fluxes pass and by which fluorescent
signals are reflected so that excitation light fluxes and fluorescent
signals are mixed with or separated from each other, and they are
installed between the pinhole array disc 6 and the micro-lens array disc
4.

[0032]Further, since a plane on which the pinholes of the pinhole array
disc 6 are arranged, a plane on the samples 2 to be observed, and
light-detecting surfaces of the cameras 14a, 14b are disposed in an
optical conjugate relation with each other, optical sectional images of
the sample 2, i.e. confocal images are formed on the cameras 14a, 14b.
Accordingly, since the confocal images of the samples 2 can be formed on
the light-detecting surfaces of the camera 14a, 14b, when the well plate
1 on which the multiple samples 2 to be inspected are arranged in a
matrix is shifted relative to the microscope 11 and the confocal scanner
90 by an XY stage (not shown), the confocal images of all samples can be
acquired by the cameras at high speed.

[0033]An operation of the drug discovery screening device shown in FIG. 1
is described next.

[0034]In FIG. 1, vertical positions of individual wells which are arranged
in a matrix on the well plate 1 are expressed in alphabets and lateral
positions thereof are expressed in numerals. In FIG. 1, there is shown a
state where the confocal image of the sample placed on the well arranged
in A1 (hereinafter referred to as A1 well) and that of the sample placed
on the well arranged in A5 (hereinafter referred to as A5 well) are
simultaneously acquired. Upon completion of the acquisition of the images
of the sample placed on A1 well and A5 well, the well plate 1 is shifted
by the XY stage to the position of next A2 well and that of A6 well so
that the confocal images of the samples placed on the A2 well and A6 well
are simultaneously acquired. Subsequently, in the same manner as the
foregoing manner, the shifting of the well plate 1 and the acquisition of
the images are repeated, thereby acquiring confocal images of the samples
two by two at a time. An example of the moving sequence by the XY stage
in this case is shown hereinafter.

[0045]According to the drug discovery screening device of the first
embodiment, since two dichroic mirrors 5a, 5b are provided within the
confocal scanner to form a confocal optical dual-system, focal images of
two samples are acquired at a time relative to the arrayed samples, so
that the throughput of the drug discovery screening device having high
accuracy can be improved twice that of the conventional drug discovery
screening device.

[0046]Further, since one confocal scanner is shared by two optical
systems, a plurality of optical systems and a plurality of wells can be
subjected to alignment easily with high accuracy.

[0047]Meanwhile, it is possible to measure not less than three samples at
a time by disposing not less than three optical systems each comprising
an objective lens, imaging lens and dichroic mirror.

[0048]Further, it is possible to dispense with the micro-lens array 4 in
case where samples generating sufficiently bright fluorescent signals are
subjected to inspection.

[0049]Meanwhile, the mixing/separating means of the excitation light
fluxes and fluorescent signals is not limited to the dichroic mirrors, it
may be replaced by an arbitrary means capable of mixing and separating
two light fluxes.

[0050]FIG. 3 shows a second embodiment of a drug discovery screening
device according to the invention, and it is a plan view of a partial
configuration thereof showing the disposition of each optical element
within a confocal scanner in the case of a confocal optical
fourfold-system. The same elements as those in FIG. 1 and FIG. 2 are
denoted by the same reference numerals and the overlapped explanations
thereof are omitted.

[0051]The drug discovery screening device shown in FIG. 3 shows a
configuration wherein a new confocal optical dual-system (reference
numerals c and d) is added to the positions orthogonal to the confocal
optical dual-system (references a and b) shown in FIG. 2. In the confocal
optical fourfold-system comprising dichroic mirrors 5a to 5d, imaging
lenses 18a to 18d (not shown), objective lenses 10a to 10d (not shown),
relay lenses 13a to 13d, and cameras 14a to 14d, the four objective
lenses 10a to 10d are disposed on each apex of a square having one side
equal to the length of the integral multiple of an interval between
respective wells of a well plate 1.

[0052]An operation of the drug discovery screening device shown in FIG. 3
is now described with reference to FIG. 4 for explaining the operation of
the well plate 1 in a first disposition example thereof.

[0053]In the case of the example of 96 well plates
([A˜H]×[1˜12]), as illustrated in the disposition table
shown in FIG. 4, an example of the shifting sequence by the XY stage 1
becomes as follows.

[0054]According to the drug discovery screening device of the second
embodiment, since four dichroic mirrors 5a, 5b are provided within the
confocal scanner to form the confocal optical fourfold-system, focal
images of four samples are acquired at a time relative to the arrayed
samples, so that the throughput of the drug discovery screening device
having high accuracy can be improved more than that of the drug discovery
screening device of the first embodiment.

[0055]The four objective lenses 10a to 10d may be disposed such that they
are disposed on each apex of a rectangle having one side equal to the
length of the integral multiple of an interval between respective wells
of the well plate 1. For example, as illustrated in FIG. 5 for explaining
the operation of the well plate 1 in the second disposition example
thereof, assuming that the initial positions are A1, E1, A7, E7, the
confocal images of the samples on all the wells can be acquired by 23
shiftings of the well plate 1.

[0056]As mentioned in detail above, according to the second embodiment of
the drug discovery screening device, it is possible to enhance the
throughput of the drug discovery screening device with high accuracy by
providing a plurality dichroic mirrors within a confocal scanner to form
a confocal optical multiple-system so as to acquire confocal images of a
plurality of samples at a time relative to the arrayed samples.

[0057]Meanwhile, at present there are following types of well plate (outer
shapes thereof are all the same)

[0058]2 columns×3 rows=6 wells

[0059]4 columns×6 rows=24 wells

[0060]8 columns×12 rows=96 wells

[0061]16 columns×24 rows=384 wells

[0062]32 columns×48 rows=153 wells

[0063]Central positions of respective wells of these well plates are
different from one another depending on the type of plate, however, if
the difference therebetween is adjusted by providing the pitch conversion
function of the objective lenses, all the wells are compatible.

[0064]The invention is not limited to the foregoing embodiments and
includes may changes and modifications without departing from the essence
of the invention.